Move ChatOps to Core

Problem to solve

ChatOps is for individual developers/operations and while it benefits teams, it's not purchased by department or company executives. It's currently in the Ultimate tier, but that feels wrong. Also, being in such a high tier hurts adoption and thus community contributions. There's an argument that based on our tiers, it should be in Starter, but we should consider moving it to Core.

Further details

We need to validate with sales that ChatOps isn't a big revenue driver for Ultimate sales. I suspect it's not, but we need to check.

Also, other things are hurting adoption such as lack of documentation and blog posts, and the fact that it's in alpha.